Method and apparatus for transmitting/receiving wireless signal in wireless communication system

ABSTRACT

A wireless communication system is disclosed. More particularly, disclosed herein are a method including receiving downlink scheduling information on a PDCCH, the downlink scheduling information comprising resource indication information (RI), selecting a first PUCCH resource set from among a plurality of PUCCH resource sets based on a size of the control information, and transmitting the control information using a PUCCH resource corresponding to the RI in the first PUCCH resource set, wherein, when a control information size supported by the first PUCCH resource set is less than or equal to X (&gt;=1) bits, the PUCCH resource is determined using one of a first scheme and a second scheme, and wherein, when the control information size supported by the first PUCCH resource set is greater than X bits, the PUCCH resource is determined using only the second scheme, and an apparatus therefor.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/354,845, filed on Mar. 15, 2019, now allowed, which is a continuationof International Application No. PCT/KR2019/000541, filed on Jan. 14,2019, which claims the benefit of U.S. Provisional Application No.62/622,732, filed on Jan. 26, 2018, and U.S. Provisional Application No.62/616,464, filed on Jan. 12, 2018. The disclosures of the priorapplications are incorporated by reference in their entirety.

TECHNICAL FIELD

The present invention relates to a wireless communication system, andmore particularly, to a method and apparatus for transmitting/receivinga wireless signal.

BACKGROUND ART

Generally, a wireless communication system is developing to diverselycover a wide range to provide such a communication service as an audiocommunication service, a data communication service and the like. Thewireless communication is a sort of a multiple access system capable ofsupporting communications with multiple users by sharing availablesystem resources (e.g., bandwidth, transmit power, etc.). For example,the multiple access system may include one of CDMA (code divisionmultiple access) system, FDMA (frequency division multiple access)system, TDMA (time division multiple access) system, OFDMA (orthogonalfrequency division multiple access) system, SC-FDMA (single carrierfrequency division multiple access) system and the like.

DISCLOSURE Technical Problem

An object of the present invention is to provide a method of efficientlytransmitting/receiving control information in a wireless communicationand an apparatus therefor.

Technical tasks obtainable from the present invention are non-limitedthe above-mentioned technical task. And, other unmentioned technicaltasks can be clearly understood from the following description by thosehaving ordinary skill in the technical field to which the presentinvention pertains.

Technical Solution

In one aspect of the present invention, provided herein is a method fortransmitting, by a communication device, control information in awireless communication system, the method including receiving downlinkscheduling information through a physical downlink control channel(PDCCH), the downlink scheduling information including resourceindication information (RI), selecting a first physical uplink controlchannel (PUCCH) resource set from among a plurality of PUCCH resourcesets based on a size of the control information, and transmitting thecontrol information using a PUCCH resource corresponding to the RI inthe first PUCCH resource set, wherein, when a control information sizesupported by the first PUCCH resource set is less than or equal to X(>=1) bits, the PUCCH resource is determined using one of a first schemeand a second scheme, and wherein, when the control information sizesupported by the first PUCCH resource set is greater than X bits, thePUCCH resource is determined using only the second scheme:

-   -   the first scheme: a pair of (the RI, an index of a resource used        for reception of the PDCCH) one-to-one corresponds to the PUCCH        resource in the first PUCCH resource set; and    -   the second scheme: the RI one-to-one corresponds to the PUCCH        resource in the first PUCCH resource set.

In another aspect of the present invention, provided herein is acommunication apparatus used in a wireless communication system,including a memory, and a processor, the processor being configured toreceive downlink scheduling information through a physical downlinkcontrol channel (PDCCH), the downlink scheduling information includingresource indication information (RI), select a first physical uplinkcontrol channel (PUCCH) resource set from among a plurality of PUCCHresource sets based on a size of the control information, and transmitthe control information using a PUCCH resource corresponding to the RIin the first PUCCH resource set, wherein, when a control informationsize supported by the first PUCCH resource set is less than or equal toX (>=1) bits, the PUCCH resource is determined using one of a firstscheme and a second scheme, and wherein, when the control informationsize supported by the first PUCCH resource set is greater than X bits,the PUCCH resource is determined using only the second scheme:

-   -   the first scheme: a pair of (the RI, an index of a resource used        for reception of the PDCCH) one-to-one corresponds to the PUCCH        resource in the first PUCCH resource set; and    -   the second scheme: the RI one-to-one corresponds to the PUCCH        resource in the first PUCCH resource set.

In another aspect of the present invention, provided herein is a methodfor receiving, by a communication apparatus, control information in awireless communication system, the method including transmittingdownlink scheduling information through a physical downlink controlchannel (PDCCH), the downlink scheduling information including resourceindication information (RI), selecting a first physical uplink controlchannel (PUCCH) resource set from among a plurality of PUCCH resourcesets based on a size of the control information, and receiving thecontrol information using a PUCCH resource corresponding to the RI inthe first PUCCH resource set, wherein, when a control information sizesupported by the first PUCCH resource set is less than or equal to X(>=1) bits, the PUCCH resource is determined using one of a first schemeand a second scheme, and wherein, when the control information sizesupported by the first PUCCH resource set is greater than X bits, thePUCCH resource is determined using only the second scheme:

-   -   the first scheme: a pair of (the RI, an index of a resource used        for reception of the PDCCH) one-to-one corresponds to the PUCCH        resource in the first PUCCH resource set; and    -   the second scheme: the RI one-to-one corresponds to the PUCCH        resource in the first PUCCH resource set.

In another aspect of the present invention, provided herein is acommunication apparatus used in a wireless communication system,including a memory, and a processor, the processor being configured totransmit downlink scheduling information through a physical downlinkcontrol channel (PDCCH), the downlink scheduling information includingresource indication information (RI), select a first physical uplinkcontrol channel (PUCCH) resource set from among a plurality of PUCCHresource sets based on a size of the control information, and receivethe control information using a PUCCH resource corresponding to the RIin the first PUCCH resource set, wherein, when a control informationsize supported by the first PUCCH resource set is less than or equal toX (>=1) bits, the PUCCH resource is determined using one of a firstscheme and a second scheme, and wherein, when the control informationsize supported by the first PUCCH resource set is greater than X bits,the PUCCH resource is determined using only the second scheme:

-   -   the first scheme: a pair of (the RI, an index of a resource used        for reception of the PDCCH) one-to-one corresponds to the PUCCH        resource in the first PUCCH resource set; and    -   the second scheme: the RI one-to-one corresponds to the PUCCH        resource in the first PUCCH resource set.

X may be 2.

When the information size supported by the first PUCCH resource set isless than or equal to X (>=1) bits, the first scheme or the secondscheme may be used based on the number of PUCCH resources in the firstPUCCH resource set.

When the information size supported by the first PUCCH resource set isless than or equal to X (>=1) bits and the number of PUCCH resources inthe first PUCCH resource set is greater than a reference value, thePUCCH resource may be determined using the first scheme, wherein thereference value may be equal to the number of values representable bythe RI.

When the information size supported by the first PUCCH resource set isless than or equal to X (>=1) bits and the number of PUCCH resources inthe first PUCCH resource set is less than or equal to a reference value,the PUCCH resource may be determined using the second scheme, whereinthe reference value may be equal to the number of values representableby the RI.

Advantageous Effects

According to the present invention, wireless signal transmission andreception can be efficiently performed in a wireless communicationsystem.

Effects obtainable from the present invention may be non-limited by theabove mentioned effect. And, other unmentioned effects can be clearlyunderstood from the following description by those having ordinary skillin the technical field to which the present invention pertains.

DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

FIG. 1 illustrates physical channels used in a 3GPP system, which is anexample of wireless communication systems, and a general signaltransmission method using the same.

FIG. 2 illustrates a radio frame structure.

FIG. 3 illustrates a resource grid of a slot.

FIG. 4 illustrates a structure of a self-contained slot.

FIG. 5 illustrates an example in which a physical channel is mapped intoa self-contained slot.

FIG. 6 illustrates a beam-based initial access procedure.

FIG. 7 illustrates an ACK/NACK transmission procedure.

FIGS. 8 to 13 illustrate a PUCCH resource allocation procedure accordingto the present invention.

FIG. 14 illustrates a base station and a user equipment applicable to anembodiment of the present invention.

BEST MODE

Embodiments of the present invention are applicable to a variety ofwireless access technologies such as code division multiple access(CDMA), frequency division multiple access (FDMA), time divisionmultiple access (TDMA), orthogonal frequency division multiple access(OFDMA), and single carrier frequency division multiple access(SC-FDMA). CDMA can be implemented as a radio technology such asUniversal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA can beimplemented as a radio technology such as Global System for Mobilecommunications (GSM)/General Packet Radio Service (GPRS)/Enhanced DataRates for GSM Evolution (EDGE). OFDMA can be implemented as a radiotechnology such as Institute of Electrical and Electronics Engineers(IEEE) 802.11 (Wireless Fidelity (Wi-Fi)), IEEE 802.16 (Worldwideinteroperability for Microwave Access (WiMAX)), IEEE 802.20, and EvolvedUTRA (E-UTRA). UTRA is a part of Universal Mobile TelecommunicationsSystem (UMTS). 3rd Generation Partnership Project (3GPP) Long TermEvolution (LTE) is part of Evolved UMTS (E-UMTS) using E-UTRA, andLTE-Advanced (A) is an evolved version of 3GPP LTE. 3GPP NR (New Radioor New Radio Access Technology) is an evolved version of 3GPP LTE/LTE-A.

As more and more communication devices require a larger communicationcapacity, there is a need for mobile broadband communication enhancedover conventional radio access technology (RAT). In addition, massiveMachine Type Communications (MTC) capable of providing a variety ofservices anywhere and anytime by connecting multiple devices and objectsis another important issue to be considered for next generationcommunications. Communication system design considering services/UEssensitive to reliability and latency is also under discussion. As such,introduction of new radio access technology considering enhanced mobilebroadband communication (eMBB), massive MTC, and Ultra-Reliable and LowLatency Communication (URLLC) is being discussed. In the presentinvention, for simplicity, this technology will be referred to as NR(New Radio or New RAT).

For the sake of clarity, 3GPP NR is mainly described, but the technicalidea of the present invention is not limited thereto.

In a wireless communication system, a user equipment (UE) receivesinformation through downlink (DL) from a base station (BS) and transmitinformation to the BS through uplink (UL). The information transmittedand received by the BS and the UE includes data and various controlinformation and includes various physical channels according totype/usage of the information transmitted and received by the UE and theBS.

FIG. 1 illustrates physical channels used in a 3GPP NR system and ageneral signal transmission method using the same.

When powered on or when a UE initially enters a cell, the UE performsinitial cell search involving synchronization with a BS in step S101.For initial cell search, the UE synchronizes with the BS and acquiresinformation such as a cell Identifier (ID) by receiving a primarysynchronization channel (P-SCH) and a secondary synchronization channel(S-SCH) from the BS. Then the UE may receive broadcast information fromthe cell on a physical broadcast channel (PBCH). In the meantime, the UEmay check a downlink channel status by receiving a downlink referencesignal (DL RS) during initial cell search.

After initial cell search, the UE may acquire more specific systeminformation by receiving a physical downlink control channel (PDCCH) andreceiving a physical downlink shared channel (PDSCH) based oninformation of the PDCCH in step S102.

The UE may perform a random access procedure to access the BS in stepsS103 to S106. For random access, the UE may transmit a preamble to theBS on a physical random access channel (PRACH) (S103) and receive aresponse message for preamble on a PDCCH and a PDSCH corresponding tothe PDCCH (S104). In the case of contention-based random access, the UEmay perform a contention resolution procedure by further transmittingthe PRACH (S105) and receiving a PDCCH and a PDSCH corresponding to thePDCCH (S106).

After the foregoing procedure, the UE may receive a PDCCH/PDSCH (S107)and transmit a physical uplink shared channel (PUSCH)/physical uplinkcontrol channel (PUCCH) (S108), as a general downlink/uplink signaltransmission procedure. Control information transmitted from the UE tothe BS is referred to as uplink control information (UCI). The UCIincludes hybrid automatic repeat and requestacknowledgement/negative-acknowledgement (HARQ-ACK/NACK), schedulingrequest (SR), channel state information (CSI), etc. The CSI includes achannel quality indicator (CQI), a precoding matrix indicator (PMI), arank indicator (RI), etc. While the UCI is transmitted on a PUCCH ingeneral, the UCI may be transmitted on a PUSCH when control informationand traffic data need to be simultaneously transmitted. In addition, theUCI may be aperiodically transmitted through a PUSCH according torequest/command of a network.

FIG. 2 illustrates a radio frame structure. In NR, uplink and downlinktransmissions are configured with frames. Each radio frame has a lengthof 10 ms and is divided into two 5-ms half-frames (HF). Each half-frameis divided into five 1-ms subframes (SFs). A subframe is divided intoone or more slots, and the number of slots in a subframe depends onsubcarrier spacing (SCS). Each slot includes 12 or 14 OrthogonalFrequency Division Multiplexing (OFDM) symbols according to a cyclicprefix (CP). When a normal CP is used, each slot includes 14 OFDMsymbols. When an extended CP is used, each slot includes 12 OFDMsymbols.

Table 1 exemplarily shows that the number of symbols per slot, thenumber of slots per frame, and the number of slots per subframe varyaccording to the SCS when the normal CP is used.

TABLE 1 SCS (15 * 2{circumflex over ( )}u) N^(slot) _(symb) N^(frame,u)_(slot) N^(subframe,u) _(slot) 15 KHz (u = 0) 14 10 1 30 KHz (u = 1) 1420 2 60 KHz (u = 2) 14 40 4 120 KHz (u = 3)  14 80 8 240 KHz (u = 4)  14160 16 N^(slot) _(symb): Number of symbols in a slot N^(frame,u)_(slot): Number of slots in a frame N^(subframe,u) _(slot): Number ofslots in a subframe

Table 2 illustrates that the number of symbols per slot, the number ofslots per frame, and the number of slots per subframe vary according tothe SCS when the extended CP is used.

TABLE 2 SCS (15 * 2{circumflex over ( )}u) N^(slot) _(symb) N^(frame,u)_(slot) N^(subframe,u) _(slot) 60 KHz (u = 2) 12 40 4

The structure of the frame is merely an example. The number ofsubframes, the number of slots, and the number of symbols in a frame mayvary.

In the NR system, OFDM numerology (e.g., SCS) may be configureddifferently for a plurality of cells aggregated for one UE. Accordingly,the (absolute time) duration of a time resource (e.g., an SF, a slot ora TTI) (for simplicity, referred to as a time unit (TU)) consisting ofthe same number of symbols may be configured differently among theaggregated cells. Here, the symbols may include an OFDM symbol (or aCP-OFDM symbol) and an SC-FDMA symbol (or a Discrete FourierTransform-spread-OFDM (DFT-s-OFDM) symbol).

FIG. 3 illustrates a resource grid of a slot. A slot includes aplurality of symbols in the time domain. For example, when the normal CPis used, the slot includes 14 symbols. However, when the extended CP isused, the slot includes 12 symbols. A carrier includes a plurality ofsubcarriers in the frequency domain. A resource block (RB) is defined asa plurality of consecutive subcarriers (e.g., 12 consecutivesubcarriers) in the frequency domain. A bandwidth part (BWP) may bedefined to be a plurality of consecutive physical RBs (PRBs) in thefrequency domain and correspond to a single numerology (e.g., SCS, CPlength, etc.). The carrier may include up to N (e.g., 5) BWPs. Datacommunication may be performed through an activated BWP, and only oneBWP may be activated for one UE. In the resource grid, each element isreferred to as a resource element (RE), and one complex symbol may bemapped to each RE.

FIG. 4 illustrates a structure of a self-contained slot. In the NRsystem, a frame has a self-contained structure in which a DL controlchannel, DL or UL data, a UL control channel, and the like may all beincluded in one slot. For example, the first N symbols (hereinafterreferred to as a DL control region) in a slot may be used to transmit aDL control channel, and the last M symbols (hereinafter referred to as aUL control region) in the slot may be used to transmit a UL controlchannel. N and M are integers greater than 0. A resource region betweenthe DL control region and the UL control region (hereinafter referred toas a data region) may be used for DL data transmission or UL datatransmission. There may be a time gap for DL-to-UL or UL-to-DL switchingbetween the control region and the data region. For example, thefollowing configurations may be considered. Corresponding intervals arelisted in temporal order.

1. DL only configuration

2. UL only configuration

3. Mixed UL-DL configuration

-   -   DL region+Guard Period (GP)+UL control region;    -   DL control region+GP+UL region,    -   DL region: (i) DL data region or (ii) DL control region+DL data        region;    -   UL region: (i) UL data region or (ii) UL data region+UL control        region.

FIG. 5 illustrates an example in which a physical channel is mapped intoa self-contained slot. A PDCCH may be transmitted in the DL controlregion, and a PDSCH may be transmitted in the DL data region. A PUCCHmay be transmitted in the UL control region, and a PUSCH may betransmitted in the UL data region. The GP provides a time gap in theprocess of switching from the transmission mode to the reception mode orfrom the reception mode to the transmission mode. Some symbols at thetime of switching from DL to UL within a subframe may be configured asthe GP.

Hereinafter, each of the physical channels will be described in moredetail.

The PDCCH carries Downlink Control Information (DCI). For example, thePCCCH (i.e., DCI) carries a transmission format and resource allocationof a downlink shared channel (DL-SCH), resource allocation informationabout an uplink shared channel (UL-SCH), paging information about apaging channel (PCH), system information present on the DL-SCH, resourceallocation information about a higher layer control message such as arandom access response transmitted on a PDSCH, a transmit power controlcommand, and activation/release of configured scheduling (CS). The DCIincludes a cyclic redundancy check (CRC). The CRC is masked/scrambledwith different identifiers (e.g., Radio Network Temporary Identifier(RNTI)) according to the owner or usage of the PDCCH. For example, ifthe PDCCH is for a specific UE, the CRC will be masked with a UEidentifier (e.g., Cell-RNTI (C-RNTI)). If the PDCCH is for paging, theCRC will be masked with a Paging-RNTI (P-RNTI). If the PDCCH is forsystem information (e.g., a system information block (SIB)), the CRCwill be masked with an system information RNTI (SI-RNTI). If the PDCCHis for a random access response, the CRC will be masked with a randomaccess-RNTI (RA-RNTI).

The PDCCH consists of 1, 2, 4, 8, or 16 Control Channel Elements (CCEs)depending on an aggregation level (AL). The CCE is a logical allocationunit used to provide a PDCCH having a predetermined code rate accordingto a radio channel state. A CCE consists of 6 Resource Element Groups(REGs). An REG is defined by one OFDM symbol and one (P)RB. The PDCCH istransmitted through a Control Resource Set (CORESET). The CORESET isdefined as an REG set having a given numerology (e.g., SCS, CP length).A plurality of CORESETs for one UE may overlap with each other in thetime/frequency domain. A CORESET may be configured through systeminformation (e.g., a Master Information Block (MIB)) or UE-specifichigher layer (e.g. Radio Resource Control (RRC) layer) signaling.Specifically, the number of RBs and the number of OFDM symbols (amaximum of 3 OFDM symbols) that constitute the CORESET may be configuredby higher layer signaling.

To receive/detect a PDCCH, the UE monitors PDCCH candidates. The PDCCHcandidates represent the CCE(s) that the UE should monitor for PDCCHdetection. Each PDCCH candidate is defined as 1, 2, 4, 8, or 16 CCEsdepending on the AL. The monitoring includes (blind) decoding of thePDCCH candidates. A set of PDCCH candidates monitored by the UE isdefined as a PDCCH Search Space (SS). The SS includes a common searchspace (CSS) or a UE-specific search space (USS). The UE may acquire DCIby monitoring the PDCCH candidates in one or more SSs configured by theMIB or higher layer signaling. Each CORESET is associated with one ormore SSs, and each of the SSs is associated with one COREST. The SSs maybe defined based on the following parameters.

-   -   controlResourceSetId: Indicates a CORESET associated with an SS;    -   monitoringSlotPeriodicityAndOffset: Indicates a PDCCH monitoring        periodicity (in units of slots) and a PDCCH monitoring interval        offset (in units of slots);    -   monitoringSymbolsWithinSlot: Indicates PDCCH monitoring symbols        in a slot (e.g. the first symbol(s) of the CORESET);    -   nrofCandidates: Indicates the number of PDCCH candidates (one of        0, 1, 2, 3, 4, 5, 6, and 8) for each AL={1, 2, 4, 8, 16}.    -   An occasion (e.g., time/frequency resources) in which PDCCH        candidates should be monitored is defined as a PDCCH        (monitoring) occasion. One or more PDCCH (monitoring) occasions        may be configured in a slot.

Table 3 exemplarily shows the features of the respective search spacetypes.

TABLE 3 Search Type Space RNTI Use Case Type0- Common SI-RNTI on aprimary cell SIB Decoding PDCCH Type0A- Common SI-RNTI on a primary cellSIB Decoding PDCCH Type1- Common RA-RNTI or TC-RNTI on a Msg2, Msg4PDCCH primary cell decoding in RACH Type2- Common P-RNTI on a primarycell Paging Decoding PDCCH Type3- Common INT-RNTI, SFI-RNTI, PDCCHTPC-PUSCH- RNTI, TPC-PUCCH-RNTI, TPC- SRS-RNTI, C-RNTI, MCS-C- RNTI, orCS-RNTI(s) UE C-RNTI, or MCS-C-RNTI, or User specific SpecificCS-RNTI(s) PDSCH decoding

Table 4 exemplarily shows DCI formats transmitted on the PDCCH.

TABLE 4 DCI format Usage 0_0 Scheduling of PUSCH in one cell 0_1Scheduling of PUSCH in one cell 1_0 Scheduling of PDSCH in one cell 1_1Scheduling of PDSCH in one cell 2_0 Notifying a group of UEs of the slotformat 2_1 Notifying a group of UEs of the PRB(s) and OFDM symbol(s)where UE may assume no transmission is intended for the UE 2_2Transmission of TPC commands for PUCCH and PUSCH 2_3 Transmission of agroup of TPC commands for SRS transmissions by one or more UEs

DCI format 0_0 may be used for scheduling of a TB-based (or TB-level)PUSCH, and DCI format 0_1 may be used for scheduling of a TB-based (orTB-level) PUSCH or a Code Block Group (CBG)-based (or CBG-level) PUSCH.DCI format 1_0 may be used for scheduling of a TB-based (or TB-level)PDSCH, and DCI format 1_1 may be used for scheduling of a TB-based (orTB-level) PDSCH or a CBG-based (or CBG-level) PDSCH (DL grant DCI). DCIformat 0_0/0_1 may be referred to as UL grant DCI or UL schedulinginformation, and DCI format 1_0/1_1 may be referred to as DL grant DCIor UL scheduling information. DCI format 2_0 is used to deliver dynamicslot format information (e.g., dynamic SFI) to the UE, and DCI format2_1 is used to deliver downlink pre-emption information to the UE. DCIformat 2_0 and/or DCI format 2_1 may be delivered to UEs in a group on agroup common PDCCH, which is a PDCCH delivered to UEs defined as onegroup.

DCI format 0_0 and DCI format 1_0 may be referred to as fallback DCIformats, and DCI format 0_1 and DCI format 1_1 may be referred to asnon-fallback DCI formats. For the fallback DCI formats, the same DCIsize/field configuration is maintained regardless of the UEconfiguration. On the other hand, for the non-fallback DCI formats, theDCI size/field configuration varies according to the UE configuration.

The PDSCH carries downlink data (e.g., DL-SCH transport block (DL-SCHTB)), and a modulation technique such as Quadrature Phase Shift Keying(QPSK), 16 Quadrature Amplitude Modulation (QAM), 64 QAM, or 256 QAM isapplied thereto. The TB is encoded to generate a codeword. The PDSCH maycarry a maximum of two codewords. Scrambling and modulation mapping maybe performed on each codeword, and the modulation symbols generated fromeach codeword may be mapped to one or more layers. Each of the layers ismapped to a resource together with a Demodulation Reference Signal(DMRS) to generate an OFDM symbol signal and transmit the signal througha corresponding antenna port.

The PUCCH carries Uplink Control Information (UCI). The UCI includes thefollowing information.

-   -   Scheduling Request (SR): Information that is used to request a        UL-SCH resource.    -   Hybrid Automatic Repeat Request (HARQ)-Acknowledgment (ACK): A        response to a downlink data packet (e.g., codeword) on the        PDSCH. HARQ-ACK indicates whether the downlink data packet has        been successfully received. In response to a single codeword,        one bit of HARQ-ACK may be transmitted. In response to two        codewords, two bits of HARQ-ACK may be transmitted. The HARQ-ACK        response includes positive ACK (simply, ACK), negative ACK        (NACK), DTX or NACK/DTX. Here, the HARQ-ACK is used        interchangeably used with HARQ ACK/NACK and ACK/NACK.    -   Channel State Information (C S I): Feedback information about a        downlink channel. Multiple Input Multiple Output (MIMO)-related        feedback information includes a Rank Indicator (RI) and a        Precoding Matrix Indicator (PMI).

Table 5 exemplarily shows PUCCH formats. PUCCH formats may be dividedinto Short PUCCHs (Formats 0 and 2) and Long PUCCHs (Formats 1, 3, and4) based on the PUCCH transmission duration.

TABLE 5 Length in OFDM Number PUCCH symbols of format N^(PUCCH) _(symb)bits Usage Etc 0 1-2  =2 HARQ, SR Sequence selection 1 4-14 =2 HARQ,[SR] Sequence modulation 2 1-2  >2 HARQ, CSI, [SR] CP-OFDM 3 4-14 >2HARQ, CSI, [SR] DFT-s-OFDM(no UE multiplexing) 4 4-14 >2 HARQ, CSI, [SR]DFT-s-OFDM(Pre DFT OCC)

PUCCH format 0 carries UCI having a size of up to 2 bits, and is mappedbased on a sequence and transmitted. Specifically, a UE transmits one ofa plurality of sequences on a PUCCH corresponding to PUCCH format 0 totransmit specific UCI to the eNB. Only when transmitting a positive SR,the UE transmits a PUCCH corresponding to PUCCH format 0 within a PUCCHresource for the corresponding SR configuration.

PUCCH format 1 carries UCI having a size of up to 2 bits, and themodulation symbols therefor are spread by an orthogonal cover code (OCC)(configured differently depending on whether frequency hopping isperformed) in the time domain. The DMRS is transmitted on a symbol onwhich a modulation symbol is not transmitted (namely, the DMRS istransmitted through time division multiplexing (TDM)).

PUCCH format 2 carries UCI having a bit size larger than 2 bits, and themodulation symbols are transmitted through frequency divisionmultiplexing (FDM) with the DMRS. The DM-RS is positioned on symbolindexes #1, #4, #7 and #10 in a resource block given with a density of⅓. A Pseudo Noise (PN) sequence is used for the DM_RS sequence. Fortwo-symbol PUCCH format 2, frequency hopping may be enabled.

PUCCH format 3 is not subjected to UE multiplexing in the same physicalresource block, but carries UCI having a bit size larger than 2 bits. Inother words, the PUCCH resource of PUCCH format 3 does not include anOCC. The modulation symbols are transmitted through time divisionmultiplexing (TDM) with the DMRS.

PUCCH format 4 supports multiplexing with up to 4 UEs in the samephysical resource blocks and carries UCI having a bit size larger than 2bits. In other words, the PUCCH resource of PUCCH format 3 includes anOCC. The modulation symbols are transmitted through time divisionmultiplexing (TDM) with the DMRS.

The PUSCH carries uplink data (e.g., UL-SCH transport block (UL-SCH TB))and/or uplink control information (UCI), and is transmitted based on aCyclic Prefix-Orthogonal Frequency Division Multiplexing (CP-OFDM)waveform or a Discrete Fourier Transform-spread-Orthogonal FrequencyDivision Multiplexing (DFT-s-OFDM) waveform. When the PUSCH istransmitted based on the DFT-s-OFDM waveform, the UE applies transformprecoding to transmit the PUSCH. For example, when the transformprecoding is not allowed (e.g., the transform precoding is disabled),the UE may transmit the PUSCH based on the CP-OFDM waveform. When thetransform precoding is allowed (e.g., the transform precoding isenabled), the UE may transmit the PUSCH based on the CD-OFDM waveform orthe DFT-s-OFDM waveform. PUSCH transmission may be dynamically scheduledby the UL grant in the DCI or semi-statically scheduled based on higherlayer (e.g., RRC) signaling (and/or Layer 1 (L1) signaling (e.g.,PDCCH)) (configured grant). The PUSCH transmission may be performed on acodebook basis or on a non-codebook basis.

FIG. 6 illustrates a beam-based initial access procedure. In 3GPP NR, aphysical channel or a reference signal may be transmitted usingbeamforming. In this case, the beams should be aligned/managed betweenthe eNB and the UE in order to perform signal transmission/reception. Inthe Radio Resource Control (RRC) IDLE mode, beam alignment may beperformed based on the SSB. In the RRC CONNECTED mode, on the otherhand, beam alignment may be performed based on the CSI-RS (in DL) andthe SRS (in UL).

Referring to FIG. 6, an eNB (e.g., a BS) may periodically transmit anSSB (S702). Here, the SSB includes PSS/SSS/PBCH. The SSB may betransmitted using beam sweeping (see FIG. 6). Thereafter, the eNB maytransmit Remaining Minimum System Information (RMSI) and Other SystemInformation (OSI) (S704). The RMSI may include information (e.g., PRACHconfiguration information) necessary for the UE to initially access theeNB. The UE performs SSB detection and then identifies the best SSB.Then, the UE may transmit an RACH preamble (Message 1 (Msg1)) to the eNBusing the PRACH resource that is linked/correspond to the index (i.e.,beam) of the best SSB (S706). The beam direction of the RACH preamble isassociated with the PRACH resource. The association between the PRACHresource (and/or the RACH preamble) and the SSB (index) may beestablished through system information (e.g., RMSI). Then, as a part ofthe RACH procedure, the eNB transmits a Random Access Response (RAR)(Msg2) in response to the RACH preamble (S708). Specifically, thescheduling information about the RAR message may be CRC-masked with aRandom Access-RNTI (RA-RNTI) and transmitted on the L1/L2 controlchannel (PDCCH). The PDCCH masked with RA-RNTI may only be transmittedthrough the common search space. Once the UE receives a schedulingsignal masked with the RA-RNTI, the UE may receive the RAR message onthe PDSCH indicated by the scheduling information. Thereafter, the UEchecks whether there is random access response information indicated tothe UE in the RAR message. Whether there is random access responseinformation indicated to the UE may be checked by checking whether thereis a Random Access Preamble ID (RAID) for the preamble transmitted bythe UE. The random access response information includes timing offsetinformation (e.g., Timing Advance Command (TAC)) for UL synchronization,UL scheduling information (e.g., UL grant), and UE temporaryidentification information (e.g., Temporary-C-RNTI (TC-RNTI)). Uponreceiving the random access response information, the UE may transmitMsg3 (e.g., RRC Connection Request) on the PUCCH using the UL grant inthe RAR (S710). Msg3 may include a UE identity for contentionresolution. Thereafter, the eNB may transmit a contention resolutionmessage Msg4 (S720). Msg4 may include RRC Connection Setup.

FIG. 7 illustrates an ACK/NACK transmission procedure. Referring to FIG.7, the UE may detect a PDCCH in slot #n. Here, the PDCCH includesdownlink scheduling information (e.g., DCI format 1_0 or 1_1). The PDCCHindicates a DL assignment-to-PDSCH offset (K0) and a PDSCH-HARQ-ACKreporting offset (K1). For example, DCI format 1_0 or 1_1 may includethe following information.

-   -   Frequency domain resource assignment: Indicates an RB set        assigned to the PDSCH.    -   Time domain resource assignment: Indicates K0 and the starting        position (e.g. OFDM symbol index) and duration (e.g. the number        of OFDM symbols) of the PDSCH in a slot.    -   PDSCH-to-HARQ feedback timing indicator: Indicates K1.

After receiving the PDSCH in slot #(n+K0) according to the schedulinginformation of slot #n, the UE may transmit UCI on the PUCCH in slot#(n+K1). Here, the UCI includes a HARQ-ACK response to the PDSCH. In thecase where the PDSCH is configured to transmit a maximum of one TB, theHARQ-ACK response may be configured in one bit. In the case where thePDSCH is configured to transmit a maximum of two TBs, the HARQ-ACKresponse may be configured in two bits if spatial bundling is notconfigured and may be configured in one bit if spatial bundling isconfigured. When slot #(n+K1) is designated as a HARQ-ACK transmissiontime for a plurality of PDSCHs, the UCI transmitted in slot #(n+K1)includes a HARQ-ACK response to the plurality of PDSCHs.

Embodiment: PUCCH Resource Allocation

In the NR system, UCI is transmitted on the PUCCH. The UCI includesHARQ-ACK, SR, and CSI. As an example of allocating PUCCH resources, theeNB may configure a plurality of PUCCH resource sets for the UE, and theUE may select a specific PUCCH resource set corresponding to a specificrange according to a range of the UCI (payload) size (e.g., the numberof UCI bits). For example, the UE may select one of the following PUCCHresource sets according to the number of UCI bits N_(UCI):

-   -   PUCCH resource set #0, if N_(UCI)≤2;    -   PUCCH resource set #1, if 2<N_(UCI)≤N₁;    -   . . . ;    -   PUCCH resource set #(K−1), if N_(K-2)<N_(UCI)≤N_(K-1).

Here, K denotes the number of PUCCH resource sets (K>1), and N_(i) isthe maximum number of UCI bits supported by PUCCH resource set #i. Forexample, PUCCH resource set #1 may be composed of resources of PUCCHformats 0 to 1, and the other PUCCH resource sets may be composed ofresources of PUCCH formats 2 to 4 (see Table 5).

Then, the eNB may transmit DCI to the UE on the PDCCH and may indicate,through an ACK/NACK Resource Indicator (ARI) in the DCI, a PUCCHresource to be utilized for UCI transmission in a specific PUCCHresource set. The ARI may be used to indicate a PUCCH resource forACK/NACK transmission and may be referred to as a PUCCH ResourceIndicator (PRI). Here, the DCI may be DCI used for PDSCH scheduling, andthe UCI may include HARQ-ACK for the PDSCH. For simplicity, the methodof explicitly indicating a specific PUCCH resource in the PUCCH resourceset using the ARI is referred to as a one-step PUCCH Resource Allocation(RA) scheme.

In addition, the eNB may configure a PUCCH resource set including PUCCHresources the number of which is larger than the number of statesrepresentable by the ARI for the UE, using a (UE-specific) higher layer(e.g., RRC) signal. In this case, the ARI may indicate a PUCCH resourcesubset in the PUCCH resource set, and a PUCCH resource to be used in theindicated PUCCH resource subset may be determined according to animplicit rule which is based on transmission resource information aboutthe PDSCH and/or the PDCCH (e.g., a starting PRB index of the PDSCH, astarting CCE index of the PDCCH, and the like). For simplicity, themethod of indicating a PUCCH resource subset with the ARI anddetermining a specific PUCCH resource in the indicated PUCCH resourcesubset according to an implicit rule is referred to as a two-step PUCCHRA scheme.

Hereinafter, a method for more efficiently allocating PUCCH resourcesusing DL control information (e.g., DCI) and an implicit rule will bedescribed.

In the present invention, a PUCCH resource may refer to a physicalresource configured with, for example, at least one of the followings: a(OFDM) symbol position at which PUCCH transmission starts, a timeduration or the number of symbols for which PUCCH transmissioncontinues, frequency domain resource allocation information (e.g., astarting position of a PRB allocation resource and the number ofallocated PRBs), information about whether frequency hopping is used, acyclic shift (CS) index, and/or an orthogonal cover code (OCC)index/length.

For example, the PUCCH resources may be classified according to thePUCCH formats as follows.

TABLE 6 PUCCH PUCCH PUCCH PUCCH PUCCH format 0 format 1 format 2 format3 format 4 Frequency Value range 0~274  0~274 0~274 0~274  0~274resource of 2nd hop if frequency hopping is enabled Index of initialConfigurability ◯ ◯ X X X cyclic shift Value range 0~11  0~11 — — —Index of time- Configurability X ◯ X X X domain OCC Value range — 0~6 —— — Length of Pre- Configurability X X X X ◯ DFT OCC Value range — — — —2, 4 Index of Pre-DFT Configurability X X X X ◯ OCC Value range — — — —0~3

In addition, the following terms are used in the present invention.

-   -   PUCCH resource superset: A set in which element(s) corresponds        to a PUCCH resource set. For example, the PUCCH resource        superset may be {PUCCH resource set #0, PUCCH resource set #1, .        . . , PUCCH resource set #(K−1)}.    -   PUCCH resource subset: A subset of a PUCCH resource set. For        example, the PUCCH resource set may be {PUCCH resource subset        #0, PUCCH resource subset #1, . . . , PUCCH resource subset        #(L−1)}. A PUCCH resource subset may consist of one or more,        preferably a plurality of, PUCCH resources.    -   (PDSCH scheduling) DCI: DCI for scheduling a PDSCH (see FIG. 7).        For example, the DCI includes DCI format 1_0 and DCI format 1_1.        The DCI is transmitted on the PDCCH.    -   Fallback DCI format: A DCI format (e.g., DCI format 1_0) in        which the DCI size/field configuration remains the same        regardless of the UE configuration.    -   Non-fallback DCI format: A DCI format (e.g., DCI format 1_1) in        which the DCI size/field configuration varies according to the        UE configuration.    -   Counter downlink assignment index (c-DAI): A specific index        value in DCI (e.g., DL scheduling DCI) that indicates an order        of (scheduled) PDSCHs (or TBs or code block groups (CBGs)). In        configuring a HARQ-ACK payload, the HARQ-ACK input bits may be        configured in the c-DAI order.    -   Total DAI (t-DAI): A specific index value in DCI (e.g., DL        scheduling DCI) that indicates the total number of PDSCHs (or        TBs or CBGs) subjected to HARQ-ACK reporting. The UE may        determine the size of the HARQ-ACK payload based on the t-DAI.

For simplicity, proposed schemes are separately described, but eachproposed scheme may be combined with other proposed schemes of thepresent invention unless they do not contradict each other.

[Proposed Scheme #1]

If it is the time immediately after the UE has performed initial accessor the time before the UE receives a (UE-specific) PUCCH resource setconfiguration through a (UE-specific) higher layer (e.g., RRC) signal,the UE cannot receive a UE-specific configuration of a PUCCH resourceset, but may only receive a cell-common or UE-common configuration. Inthis case, when multiple UEs utilize the same PUCCH resource set,collision between PUCCH resources may become worse or fewer PUCCHresources may be available. For example, the eNB may configure acell-commonly used PUCCH resource set through the RMSI (or SIB), whichis a kind of system information, and the UE may perform the two-stepPUCCH RA using the ARI and an implicit rule (that is based on thestarting CCE index of the DL scheduling DCI and the like). In this case,to distinguish between the PUCCH resources for the UEs if possible, aPUCCH resource set that the eNB provides through the system information(e.g., RMSI, SIB) may be configured to be large (namely, the PUCCHresource set may include a large number of PUCCH resources). In thiscase, the PUCCH resource set includes more PUCCH resources than thenumber of states representable by the ARI, and the UE selects one ofmultiple PUCCH resource candidates by an implicit rule. Accordingly, thecapability of controlling PUCCH resource allocation/scheduling formultiple UEs may be low in view of the eNB (or network).

In order to address the above-described issue, in transmitting HARQ-ACKfor a PDSCH, the UE may determine a PUCCH resource according to the RNTIand the type of the PDSCH and/or PDCCH. Accordingly, even before a(UE-specific) higher layer signal is received, the PUCCH resource setsmay be identified for each UE. The PUCCH resource may be determined asfollows.

(1) Step 1: The eNB may configure a plurality of PUCCH resource sets (ora PUCCH resource superset) for the UE through the system information.The system information may be an RMSI (or SIB) and/or other systeminformation (OSI).

(2) Step 2: A specific PUCCH resource set may be selected from among theplurality of PUCCH resource sets (or the PUCCH resource superset) usingone of the following methods.

A. Opt. 1: The UE may select a specific PUCCH resource set from amongthe plurality of PUCCH resource sets (or the PUCCH resource superset)according to the type of the received PDSCH and/or PDCCH. For example,the type of the PDSCH and PDCCH may be classified according to thefollowing criteria:

-   -   1. Whether or not the PDSCH is Msg4;    -   2. Whether the PDCCH is fallback DCI or non-fallback DCI; and    -   3. The DCI format of the PDCCH.

B. Opt. 2: The UE may select a specific PUCCH resource set from amongthe plurality of PUCCH resource sets (or the PUCCH resource superset)based on the RNTI and/or the DCI for scheduling Msg2.

-   -   1. The RNTI may be an RNTI received in the RACH procedure (e.g.,        RA-RNTI, TC-RNTI).    -   2. Bit fields (e.g., a PUCCH resource indicator (e.g., ARI), a        PUCCH transmission timing indicator, etc.) related to PUCCH        resource allocation/transmission in the DCI for scheduling Msg2        may be used in the operation of selecting the specific PUCCH        resource set from among the plurality of PUCCH resource sets (or        the PUCCH resource superset).

(3) Step 3: A specific PUCCH resource subset in the PUCCH resource setmay be indicated by (PDSCH scheduling) DCI. As an example, the PUCCHresource subset in the PUCCH resource set may be indicated by the ARI inthe (PDSCH scheduling) DCI.

(4) Step 4: A specific PUCCH resource may be selected in the PUCCHresource subset according to a (PDSCH or PDCCH transmission resourceinformation-based) implicit rule. As an example, the implicit rule maybe a scheme of selecting the specific PUCCH resource in the PUCCHresource subset based on one or more of the following parameters:

-   -   1. a (starting) CCE index on which a (PDSCH scheduling) PDCCH is        transmitted;    -   2. a PDCCH candidate index on which the (PDSCH scheduling) PDCCH        is transmitted;    -   3. a DL control region index in which the (PDSCH scheduling)        PDCCH is transmitted;    -   4. a (starting) PRB index of a PDSCH region indicated by the        (PDSCH scheduling) PDCCH;    -   5. HARQ-ACK timing indicated by the (PDSCH scheduling) PDCCH;    -   6. a UL BWP index (e.g., a BWP index for PUCCH transmission)        indicated by the (PDSCH scheduling) PDCCH;    -   7. a slot index in which the (PDSCH scheduling) PDCCH is        transmitted;    -   8. a slot index in which the PDSCH is transmitted; and    -   9. a slot index in which the PUCCH is transmitted.

Here, if only one PUCCH resource is left in a specific step, the PUCCHresource may be selected, and the subsequent steps may be skipped.

FIG. 8 illustrates a PUCCH resource allocation procedure according tothe this scheme. In this scheme, the PUCCH resource is selected in threesteps (i.e., three-step PUCCH RA).

Referring to FIG. 8, the 4-bit information in the RMSI represents 16code points, and each of the code points may indicate one of (a maximumof) 16 PUCCH resource supersets. For example, ‘0010’ may indicate PUCCHresource superset #1. Each PUCCH resource superset may be composed of(up to) 8 PUCCH resource sets.

Thereafter, one PUCCH resource set may be selected from among the eightPUCCH resource sets in the PUCCH resource superset based on the PDSCHand/or PDCCH type or the RNTI and/or Msg2 scheduling DCI according tothe operation of Step 2. The eNB may indicate one specific PUCCHresource subset in each PUCCH resource set through the (PDSCHscheduling) DCI. When there are two or more PUCCH resources in the PUCCHresource subset, one PUCCH resource may be selected according to a(PDSCH and/or PDCCH transmission resource information-based) implicitrule. Specifically, the following methods may be considered.

In one example, the eNB may configure two PUCCH resource sets (e.g., SetA and Set B) in the PUCCH resource superset through the RMSI. The UE mayselect Set A if the PDSCH corresponding to the HARQ-ACK is scheduled byfallback DCI (e.g., DCI format 1_0) and select Set B if the PDSCH isscheduled by non-fallback DCI (e.g., DCI format 1_1). Then, the UE mayselect a PUCCH resource subset in the selected PUCCH resource set usingthe ARI in the DCI. If there are two or more elements in the selectedPUCCH resource subset, the UE may determine one PUCCH resource accordingto a (PDSCH or PDCCH transmission resource information-based) implicitrule. Accordingly, the HARQ-ACK transmission PUCCH resource sets for UEshaving a PDSCH scheduled by fallback DCI may be distinguished from thosefor UEs having a PDSCH scheduled by non-fallback DCI.

In another example, the eNB may configure N PUCCH resource sets in thePUCCH resource superset through the RMSI. The UE select one PUCCHresource set from among the N PUCCH resource sets based on the RNTI (ortemporary UE ID (e.g., TC-RNTI)) received in the RACH procedure and/orthe Msg2 scheduling DCI. As an example, indexing of the N PUCCHresources sets configured through the RMSI may be predefined, and aPUCCH resource set corresponding to an index value derived by applyingModulo N to the RNTI value may be selected. As another example, the UEdoes not perform PUCCH transmission for the PDSCH corresponding to Msg2.However, in order to maintain consistency of a DCI format in the DCI forscheduling Msg2, there may still be bit fields for indicating PUCCHresource allocation and a PUSCH transmission time as in the case of DCIfor scheduling a normal PDSCH. In this case, the bit fields forindicating the PUCCH resource allocation and the PUSCH transmission timein the DCI for scheduling Msg2 may be re-interpreted as being used toindicate one of the N PUCCH resource sets in the PUCCH resource supersetindicated by the RMSI. The UE may then select one PUCCH resource subsetin the selected PUCCH resource set through the ARI. If there are two ormore elements in the selected PUCCH resource subset, the UE maydetermine one PUCCH resource according to a (PDSCH or PDCCH transmissionresource information-based) implicit rule. Accordingly, UEs to performPUCCH transmission may be divided into N groups based on the RNTI or theMsg2 DCI, and PUCCH resource sets (physically) distinguished from eachother may be allocated to the N groups, respectively.

Thereafter, the UEs may transmit UCI to the eNB using the selected PUCCHresource. The UCI may include HARQ-ACK.

[Proposed Scheme #2]

As described above, the eNB may configure a plurality of PUCCH resourcesets for the UE, and the UE may select a specific PUCCH resource setcorresponding to a specific range according to the range of the UCIpayload size. Then, the eNB may transmit DCI to the UE on the PDCCH andmay indicate, through the ARI in the DCI, a PUCCH resource to be usedfor UCI transmission in the specific PUCCH resource set. Here, the DCImay be DCI used for PDSCH scheduling, and the UCI may include HARQ-ACKfor the PDSCH. In this case, if the PUCCH resource set is composed ofmore PUCCH resources than the number of states representable by the ARI,the ARI may indicate a PUCCH resource subset in the PUCCH resource set,and a PUCCH resource to be used in the indicated PUCCH resource subsetmay be determined according to an implicit rule which is based ontransmission resource information about the PDSCH and/or the PDCCH(e.g., a starting PRB index, a starting CCE index, and the like). Forsimplicity, the two-step PUCCH RA will be referred to as Method A andthe one-step PUCCH RA will be referred to as Method B in the followingdescription.

When HARQ-ACKs for a plurality of PDSCHs are to be UCI-multiplexed andtransmitted on a single PUCCH resource, the eNB should schedule each ofthe plurality of PDSCHs, and allocate the same PUCCH resource for thecorresponding HARQ-ACK transmissions. When Method A is applied, the eNBshould not only configure the same ARI value for the plurality ofPDSCHs, but also limit the parameters applied to the implicit rule so asto indicate the same PUCCH resource. In this case, when the implicitrule has the PDCCH or PDCCH transmission resource information (e.g., thestarting PRB index of the PDSCH, the starting CCE index of the PDCCH,and the like) as an input parameter, scheduling of the PDSCH or thePDCCH may be restricted in order to indicate the same PUCCH resource. Asone method to address this issue, the PUCCH RAs of both Method A andMethod B may be allowed only for a PUCCH resource set (e.g., a PUCCHresource set for UCI transmission of 2 or fewer bits) that is notexpected to UCI-multiplex the HARQ-ACKs for the plurality of PDSCHs. Forthe other PUCCH resource sets (e.g., a PUCCH resource set for UCItransmission of more than 2 bits), only the PUCCH RA of Method B may beallowed.

That is, the PUCCH RAs of Method A and/or Method B may be supported fora PUCCH resource set for transmission of UCI (e.g., HARQ-ACK) smallerthan or equal to X bits (e.g., X=2), and only the PUCCH RA of Method Bmay be applied to a PUCCH resource set for transmission of UCI (e.g.,HARQ-ACK) larger than X bits. Here, the PUCCH resource set supportingtransmission of UCI smaller than or equal to X bits (e.g., X=2) may beunderstood as a PUCCH resource set in which only HARQ-ACK bitscorresponding to a single PDSCH can be transmitted. For example, thePUCCH resource set in which only HARQ-ACK bits corresponding to a singlePDSCH can be transmitted may include a PUCCH resource set including aPUCCH format 0 resource and/or a PUCCH format 1 resource.

(1) Method A (=two-step PUCCH RA): A (single) PUCCH resource subset inthe PUCCH resource set may be indicated by (PDSCH scheduling) DCI, and a(single) PUCCH resource may be selected in the PUCCH resource subsetaccording to a (PDSCH or PDCCH transmission resource information-based)implicit rule. Here, the PDSCH transmission resource information mayinclude a starting PRB index of the PDSCH, and the PDCCH transmissionresource information may include a starting CCE index of the PDCCH. FIG.9 illustrates PUCCH resource allocation according to Method A. In MethodA, a pair of (ARI, PDSCH or PDCCH transmission resource information) maybe mapped to a single PUCCH for UCI transmission (one-to-one mapping).For example, a pair of (ARI, CCE index) may be mapped to a single PUCCHfor UCI transmission.

(2) Method B (=one-step PUCCH RA): A (single) PUCCH resource in thePUCCH resource set may be indicated by (PDSCH scheduling) DCI. FIG. 10illustrates PUCCH resource allocation according to Method B. In MethodB, the ARI may be mapped to a single PUCCH for UCI transmission(one-to-one mapping).

FIGS. 11 to 13 illustrate a PUCCH resource allocation procedureaccording to the present invention. Here, the PUCCH resources mayinclude a PUCCH resource for HARQ-ACK transmission. For example, theprocedures of FIGS. 11 to 13 may be part of the resource allocationprocedure for PUCCH transmission of FIG. 7.

Referring to FIG. 11, the UE may select a PUCCH resource set from amonga plurality of PUCCH resource sets based on the UCI size (S1102). Theplurality of PUCCH resource sets may be configured by a higher layer(e.g., RRC) signal as follows.

-   -   PUCCH resource set #0, if Number of UCI bits≤2;    -   PUCCH resource set #1, if 2<Number of UCI bits≤N₁;    -   . . . ;    -   PUCCH resource set #(K−1), if N_(K-2)<Number of UCI        bits≤N_(K-1).

Here, K denotes the number of PUCCH resource sets (K>1), and N_(i) isthe maximum number of UCI bits supported by PUCCH resource set #i.

Thereafter, the UE may check whether the selected PUCCH resource set isfor “Number of UCI bits≤X (e.g., 2) bits” (S1104). If the selected PUCCHresource set is for “Number of UCI bits≤X (e.g., 2) bits,” the UE maydetermine a PUCCH resource for UCI transmission in the selected PUCCHresource set based on either Method A or Method B. The UCI includesHARQ-ACK (S1106). On the other hand, if the selected PUCCH resource setis not for “Number of UCI bits≤X (e.g., 2) bits” (i.e., “Number of UCIbits>X”), the UE may determine a PUCCH resource for UCI transmission inthe selected PUCCH resource set based on Method B only (S1108).

FIG. 12 is basically the same as FIG. 11. The difference from FIG. 11 isthat S1106 in FIG. 11 is subdivided into S1206 a, S1206 b, and S1206 cin FIG. 12. Thus, only S1206 a, S1206 b, and S1206 c will be described.If the PUCCH resource set is for “Number of UCI bits≤X (e.g., 2) bits”as a result of operation S1204, the UE may check whether the number ofPUCCH resources in the PUCCH resource set is greater than Y (S1206 a).Here, Y may have the same value as the number of states representable bythe ARI (for example, Y=4 when the ARI has 2 bits and Y=8 when the ARIhas 3 bits). As a result, if the number of PUCCH resources in the PUCCHresource set is greater than Y, the UE may determine a PUCCH resourcefor UCI transmission in the PUCCH resource set based on Method A (S1206b). On the other hand, if the number of PUCCH resources in the PUCCHresource set is less than or equal to Y, the UE may determine a PUCCHresource for UCI transmission in the PUCCH resource set based on MethodB (S1206 c).

FIG. 13 is basically the same as FIG. 12. The difference from FIG. 12 isthat S1204 and S1206 a in FIG. 12 are combined into S1304, and S1206 cand S1208 in FIG. 12 are combined into S1308. Thus, if 1) the PUCCHresource set is for “Number of UCI bits≤X (e.g., 2) bits” and 2) thenumber of PUCCH resources in the PUCCH resource set is greater than Y,the UE may determine a PUCCH resource for UCI transmission in the PUCCHresource set based on Method A (S 1306). On the other hand, if any of 1)and 2) is not satisfied, the UE may determine a PUCCH resource for UCItransmission in the PUCCH resource set based on Method B (S1308).

[Proposed Scheme #3]

In the NR system, the system bandwidth in a carrier is very large, andthus the system bandwidth may not be fully utilized depending on the RFcharacteristics of the UE. Therefore, the entire system bandwidth may bedivided into a plurality of BWPs. Each BWP may include a bandwidth and aposition of a frequency-domain resource and may also include OFDMnumerology information to be applied to the frequency resource. In thiscase, if the eNB indicates a HARQ-ACK transmission PUCCH resourcecorresponding to PDSCH transmission through the (PDSCH scheduling) DCI,the UL BWP that is valid at the reception time of the PDSCH may differfrom the UL BWP that is valid at the transmission time of the HARQ-ACKPUCCH. In order to support the above-described operation, the eNB needsto signal, to the UE, information about a BWP at which a PUCCH resourceis transmitted.

To address the above-described issue, the eNB may signal, to the UE, BWPinformation about a specific PUCCH resource using one or more of thefollowing methods.

(1) BWP information may be configured for each PUCCH resource.

(2) The BWP at which a PUCCH resource is to be transmitted may beindicated through DCI. Here, the DCI may be (PDSCH scheduling) DCI orgroup-common DCI.

[Proposed Scheme #4]

In the NR system, the c-DAI may be utilized to determine the HARQ-ACKpayload when the UE transmits HARQ-ACK information corresponding to aplurality of PDSCHs on a single PUCCH resource. If it is time before RRCconnection setup after the initial access, the UE may not perform theoperation of transmitting HARQ-ACKs for the plurality of PDSCHs on asingle PUCCH resource. In particular, on a PUCCH resource utilizedbefore RRC connection setup, only transmission of HARQ-ACK bitscorresponding to a single PDSCH may be allowed. However, if there is abit field (hereinafter, Field A) for the c-DAI in the (DL scheduling)DCI performing the fallback operation, Field A may always be present inthe DCI to maintain a constant DCI size. Here, before the RRC connectionsetup, Field A may not be used for the DAI, and thus may be used foranother purpose. Accordingly, in the present invention, when there is abit field (hereinafter, Field B) for indicating a PUCCH resource in the(DL scheduling) DCI, the bit width of the bit filed may be extended byadding Field A to Field B before the RRC connection setup. After the RRCconnection setup, Field A and Field B may be used for c-DAI and PUCCHresource indication, respectively. Alternatively, the c-DAI may be usedfor other purposes if a (UE-specific) PUCCH resource set (of K or morebits) supporting HARQ-ACK transmission for a plurality of PDSCHs has notbeen configured for the UE. Therefore, before the (UE-specific) PUCCHresource set (of K or more bits) is configured for the UE, Field A maybe added to Field B to extend the bit width of the bit field for PUCCHresource indication. After the (UE-specific) PUCCH resource set (of K ormore bits) is configured for the UE, Field A and Field B may be used forthe c-DAI and the PUCCH resource indication, respectively.

That is, when an X1-bit field (hereinafter, Field A) and an X2 bit field(hereinafter, Field B) are included in the (DL scheduling) DCI, Fields Aand B may be used differently according to the following specificconditions. Accordingly, even before a (UE-specific) higher layer signalis received, the PUCCH resource sets for the respective UEs may bedistinguished from each other.

(1) Opt. 1: the fields are used differently depending on whether or notthe RRC connection setup is made,

A. Before the RRC connection setup: Field A+Field B may be used forindication of a PUCCH resource (in the PUCCH resource set).

B. After the RRC connection setup: Field A may be used for DAI (e.g.c-DAI) and Field B may be used for indication of a PUCCH resource (inthe PUCCH resource set).

(2) Opt. 2: the fields are used differently depending on whether a(UE-specific) PUCCH resource set (of K or more bits) is configured.

A. Before a (UE-specific) PUCCH resource set is configured (when the setis configured): Field A+Field B may be used for indication of a PUCCHresource (in the PUCCH resource set).

B. After a (UE-specific) PUCCH resource set is configured (when the setis not configured): Field A may be used for DAI (e.g. c-DAI) and Field Bmay be used for indication of a PUCCH resource (in the PUCCH resourceset).

In the above-described scheme, the number of resources in the PUCCHresource set before the RRC connection setup (or before configuration ofthe (UE-specific) PUCCH resource set) may be set to be larger than thenumber of resources in the PUCCH resource set after the RRC connectionsetup (or after configuration of the (UE-specific) PUCCH resource set),in proportion to the number of bits of Field A or the number of statesrepresented by the field.

FIG. 14 illustrates a BS and a UE of a wireless communication system,which are applicable to embodiments of the present invention.

Referring to FIG. 14, the wireless communication system includes a BS110 and a UE 120. When the wireless communication system includes arelay, the BS or UE may be replaced by the relay.

The BS 110 includes a processor 112, a memory 114 and a radio frequency(RF) unit 116. The processor 112 may be configured to implement theprocedures and/or methods proposed by the present invention. The memory114 is connected to the processor 112 and stores information related tooperations of the processor 112. The RF unit 116 is connected to theprocessor 112 and transmits and/or receives an RF signal. The UE 120includes a processor 122, a memory 124 and an RF unit 126. The processor122 may be configured to implement the procedures and/or methodsproposed by the present invention. The memory 124 is connected to theprocessor 122 and stores information related to operations of theprocessor 122. The RF unit 126 is connected to the processor 122 andtransmits and/or receives an RF signal.

The embodiments of the present invention described hereinbelow arecombinations of elements and features of the present invention. Theelements or features may be considered selective unless otherwisementioned. Each element or feature may be practiced without beingcombined with other elements or features. Further, an embodiment of thepresent invention may be constructed by combining parts of the elementsand/or features. Operation orders described in embodiments of thepresent invention may be rearranged. Some constructions of any oneembodiment may be included in another embodiment and may be replacedwith corresponding constructions of another embodiment. It will beobvious to those skilled in the art that claims that are not explicitlycited in each other in the appended claims may be presented incombination as an embodiment of the present invention or included as anew claim by a subsequent amendment after the application is filed.

In the embodiments of the present invention, a description is madecentering on a data transmission and reception relationship among a BS,a relay, and an MS. In some cases, a specific operation described asperformed by the BS may be performed by an upper node of the BS. Namely,it is apparent that, in a network comprised of a plurality of networknodes including a BS, various operations performed for communicationwith an MS may be performed by the BS, or network nodes other than theBS. The term ‘BS’ may be replaced with the term ‘fixed station’, ‘NodeB’, ‘enhanced Node B (eNode B or eNB)’, ‘access point’, etc. The term‘UE’ may be replaced with the term ‘Mobile Station (MS)’, ‘MobileSubscriber Station (MSS)’, ‘mobile terminal’, etc.

The embodiments of the present invention may be achieved by variousmeans, for example, hardware, firmware, software, or a combinationthereof. In a hardware configuration, the methods according to theembodiments of the present invention may be achieved by one or moreApplication Specific Integrated Circuits (ASICs), Digital SignalProcessors (DSPs), Digital Signal Processing Devices (DSPDs),Programmable Logic Devices (PLDs), Field Programmable Gate Arrays(FPGAs), processors, controllers, microcontrollers, microprocessors,etc.

In a firmware or software configuration, the embodiments of the presentinvention may be implemented in the form of a module, a procedure, afunction, etc. For example, software code may be stored in a memory unitand executed by a processor. The memory unit is located at the interioror exterior of the processor and may transmit and receive data to andfrom the processor via various known means.

Those skilled in the art will appreciate that the present invention maybe carried out in other specific ways than those set forth hereinwithout departing from the spirit and essential characteristics of thepresent invention. The above embodiments are therefore to be construedin all aspects as illustrative and not restrictive. The scope of theinvention should be determined by the appended claims and their legalequivalents, not by the above description, and all changes coming withinthe meaning and equivalency range of the appended claims are intended tobe embraced therein.

INDUSTRIAL APPLICABILITY

The present invention is applicable to UEs, eNBs or other apparatuses ofa wireless mobile communication system.

1. A method for performing uplink transmission by a communication devicein a wireless communication system, the method comprising: receivingdownlink control information (DCI) for downlink scheduling, the DCIcomprising resource indication information (RI); receiving downlink dataindicated by the DCI; and transmitting uplink control information (UCI)including hybrid automatic repeat request acknowledgement (HARQ-ACK)information for the downlink data using a PUCCH resource correspondingto the RI in a PUCCH resource set, wherein the PUCCH resource set isselected from a plurality of PUCCH resource sets based on a size of theUCI, wherein, based on a UCI size supported by the PUCCH resource setbeing less than or equal to X (>=1) bits, the PUCCH resource isdetermined using one of a first scheme and a second scheme, and wherein,based on the UCI size supported by the PUCCH resource set being greaterthan X bits, the PUCCH resource is determined using only the secondscheme: the first scheme: the PUCCH resource in the PUCCH resource setis determined based on both the RI and an index of a resource used forreception of the DCI; and the second scheme: the PUCCH resource in thePUCCH resource set is determined based on the RI only.
 2. The methodaccording to claim 1, wherein X is
 2. 3. The method according to claim2, wherein, when the UCI size supported by the PUCCH resource set isless than or equal to X (>=1) bits, the first scheme or the secondscheme is used based on the number of PUCCH resources in the PUCCHresource set.
 4. The method according to claim 3, wherein, when the UCIsize supported by the PUCCH resource set is less than or equal to X(>=1) bits and the number of PUCCH resources in the PUCCH resource setis greater than a reference value, the PUCCH resource is determinedusing the first scheme, wherein the reference value is equal to thenumber of values representable by the RI.
 5. The method according toclaim 3, wherein, when the UCI size supported by the PUCCH resource setis less than or equal to X (>=1) bits and the number of PUCCH resourcesin the first PUCCH resource set is less than or equal to a referencevalue, the PUCCH resource is determined using the second scheme, whereinthe reference value is equal to the number of values representable bythe RI.
 6. A communication apparatus for use in a wireless communicationsystem, comprising: a memory; and a processor, the processor beingconfigured to: receive downlink control information (DCI) for downlinkscheduling information, the DCI comprising resource indicationinformation (RI); receive downlink data indicated by the DCI; andtransmit uplink control information (UCI) including hybrid automaticrepeat request acknowledgement (HARQ-ACK) information for the downlinkdata using a PUCCH resource corresponding to the RI in a PUCCH resourceset, wherein the PUCCH resource set is selected from a plurality ofPUCCH resource sets based on a size of the UCI, wherein, based on a UCIsize supported by the PUCCH resource set being less than or equal to X(>=1) bits, the PUCCH resource is determined using one of a first schemeand a second scheme, and wherein, based on the UCI size supported by thePUCCH resource set being greater than X bits, the PUCCH resource isdetermined using only the second scheme: the first scheme: the PUCCHresource in the PUCCH resource set is determined based on both the RIand an index of a resource used for reception of the DCI; and the secondscheme: the PUCCH resource in the PUCCH resource set is determined basedon the RI only.
 7. The communication apparatus according to claim 6,wherein X is
 2. 8. The communication apparatus according to claim 7,wherein, when the UCI size supported by the PUCCH resource set is lessthan or equal to X (>=1) bits, the first scheme or the second scheme isused based on the number of PUCCH resources in the PUCCH resource set.9. The communication apparatus according to claim 8, wherein, when theUCI size supported by the PUCCH resource set is less than or equal to X(>=1) bits and the number of PUCCH resources in the PUCCH resource setis greater than a reference value, the PUCCH resource is determinedusing the first scheme, wherein the reference value is equal to thenumber of values representable by the RI.
 10. The communicationapparatus according to claim 8, wherein, when the UCI size supported bythe PUCCH resource set is less than or equal to X (>=1) bits and thenumber of PUCCH resources in the PUCCH resource set is less than orequal to a reference value, the PUCCH resource is determined using thesecond scheme, wherein the reference value is equal to the number ofvalues representable by the RI.
 11. A method for receiving controlinformation by a communication apparatus in a wireless communicationsystem, the method comprising: transmitting downlink control information(DCI) for downlink scheduling, the DCI comprising resource indicationinformation (RI); transmitting downlink data indicated by the DCI; andreceiving uplink control information (UCI) including hybrid automaticrepeat request acknowledgement (HARQ-ACK) information for the downlinkdata using a PUCCH resource corresponding to the RI in a PUCCH resourceset, wherein the PUCCH resource set is selected from a plurality ofPUCCH resource sets based on a size of the UCI, wherein, based on a UCIsize supported by the PUCCH resource set being less than or equal to X(>=1) bits, the PUCCH resource is determined using one of a first schemeand a second scheme, and wherein, based on the UCI size supported by thePUCCH resource set being greater than X bits, the PUCCH resource isdetermined using only the second scheme: the first scheme: the PUCCHresource in the PUCCH resource set is determined based on both the RIand an index of a resource used for reception of the DCI; and the secondscheme: the PUCCH resource in the PUCCH resource set is determined basedon the RI only.
 12. The method according to claim 11, wherein X is 2.13. The method according to claim 12, wherein, when the UCI sizesupported by the PUCCH resource set is less than or equal to X (>=1)bits, the first scheme or the second scheme is used based on the numberof PUCCH resources in the PUCCH resource set.
 14. The method accordingto claim 13, wherein, when the UCI size supported by the PUCCH resourceset is less than or equal to X (>=1) bits and the number of PUCCHresources in the PUCCH resource set is greater than a reference value,the PUCCH resource is determined using the first scheme, wherein thereference value is equal to the number of values representable by theRI.
 15. The method according to claim 13, wherein, when the UCI sizesupported by the PUCCH resource set is less than or equal to X (>=1)bits and the number of PUCCH resources in the PUCCH resource set is lessthan or equal to a reference value, the PUCCH resource is determinedusing the second scheme, wherein the reference value is equal to thenumber of values representable by the RI.
 16. A communication apparatusfor use in a wireless communication system, comprising: a memory; and aprocessor, the processor being configured to: transmit downlink controlinformation (DCI) for downlink scheduling, the DCI comprising resourceindication information (RI); transmit downlink data indicated by theDCI; and receive uplink control information (UCI) including hybridautomatic repeat request acknowledgement (HARQ-ACK) information for thedownlink data using a PUCCH resource corresponding to the RI in a PUCCHresource set, wherein the PUCCH resource set is selected from aplurality of PUCCH resource sets based on a size of the UCI, wherein,based on a UCI size supported by the PUCCH resource set being less thanor equal to X (>=1) bits, the PUCCH resource is determined using one ofa first scheme and a second scheme, and wherein, based on the UCI sizesupported by the PUCCH resource set being greater than X bits, the PUCCHresource is determined using only the second scheme: the first scheme:the PUCCH resource in the PUCCH resource set is determined based on boththe RI and an index of a resource used for reception of the DCI; and thesecond scheme: the PUCCH resource in the PUCCH resource set isdetermined based on the RI only.
 17. The communication apparatusaccording to claim 16, wherein X is
 2. 18. The communication apparatusaccording to claim 17, wherein, when the UCI size supported by the PUCCHresource set is less than or equal to X (>=1) bits, the first scheme orthe second scheme is used based on the number of PUCCH resources in thePUCCH resource set.
 19. The communication apparatus according to claim18, wherein, when the UCI size supported by the PUCCH resource set isless than or equal to X (>=1) bits and the number of PUCCH resources inthe PUCCH resource set is greater than a reference value, the PUCCHresource is determined using the first scheme, wherein the referencevalue is equal to the number of values representable by the RI.
 20. Thecommunication apparatus according to claim 18, wherein, when the UCIsize supported by the PUCCH resource set is less than or equal to X(>=1) bits and the number of PUCCH resources in the PUCCH resource setis less than or equal to a reference value, the PUCCH resource isdetermined using the second scheme, wherein the reference value is equalto the number of values representable by the RI.